﻿OF 
  CARBONIFEROUS 
  GASTEROPODA. 
  621 
  

  

  of 
  growth 
  are 
  not 
  very 
  distinct 
  except 
  on 
  trie 
  base 
  ; 
  they 
  appear 
  to 
  

   come 
  straight 
  down 
  the 
  whorls, 
  being 
  merely 
  deflected 
  by 
  the 
  

   keels. 
  

  

  Length 
  of 
  small 
  specimen 
  of 
  twelve 
  whorls 
  4 
  millim., 
  width 
  of 
  

   body-whorl 
  1| 
  millim. 
  A 
  larger 
  specimen 
  has 
  only 
  four 
  whorls 
  

   preserved, 
  it 
  is 
  3 
  millim. 
  in 
  length, 
  and 
  the 
  body- 
  whorl 
  is 
  1^ 
  millim. 
  

   in 
  width. 
  

  

  This 
  shell 
  bears 
  some 
  resemblance 
  to 
  species 
  of 
  MureJiisonia, 
  but 
  

   the 
  absence 
  of 
  a 
  sinus 
  in 
  the 
  outer 
  lip 
  excludes 
  it 
  from 
  that 
  genus 
  ; 
  

   from 
  species 
  of 
  Aclisina 
  it 
  may 
  be 
  distinguished 
  by 
  the 
  form 
  of 
  the 
  

   mouth 
  and 
  the 
  flattened, 
  closely 
  set, 
  whorls. 
  I 
  feel 
  somewhat 
  

   doubtful 
  about 
  referring 
  it 
  to 
  the 
  genus 
  Orthonema, 
  as 
  it 
  is 
  more 
  

   elongated 
  and 
  the 
  whorls 
  are 
  less 
  angular 
  than 
  in 
  any 
  species 
  of 
  that 
  

   genus 
  I 
  have 
  seen 
  figured 
  ; 
  I, 
  however, 
  know 
  of 
  no 
  other 
  genus 
  to 
  

   species 
  of 
  which 
  it 
  bears 
  a 
  closer 
  resemblance, 
  and 
  it 
  may 
  therefore 
  

   be 
  well 
  to 
  place 
  it 
  with 
  Ortlionema 
  for 
  the 
  present. 
  

  

  Locality. 
  Glencart, 
  Dairy. 
  

  

  Formation. 
  Upper 
  Limestone 
  series. 
  

  

  It 
  is, 
  I 
  think, 
  unnecessary 
  to 
  repeat 
  a 
  description 
  of 
  the 
  genus 
  

   Marcliisonia 
  here, 
  as 
  it 
  was 
  pretty 
  fully 
  given 
  in 
  a 
  previous 
  paper 
  *, 
  

   in 
  which 
  also 
  I 
  mentioned 
  that 
  J. 
  W. 
  Salter 
  had 
  separated 
  from 
  the 
  

   typical 
  MureJiisonia 
  a 
  group 
  of 
  shells 
  distinguished 
  by 
  certain 
  

   characteristics 
  under 
  the 
  name 
  Hormotoma 
  f, 
  and 
  that 
  "Whitfield 
  had 
  

   formed 
  a 
  distinct 
  genus 
  of 
  others 
  under 
  the 
  name 
  of 
  Lopliospira 
  J. 
  

   Since 
  then 
  D. 
  P. 
  CEhlert 
  has 
  grouped 
  some 
  species 
  of 
  Murcliisonia 
  

   in 
  two 
  more 
  sections, 
  called 
  Ooniostroplia 
  and 
  Ccelocaulus§. 
  

  

  To 
  the 
  former 
  of 
  these 
  alone 
  I 
  need 
  refer 
  in 
  this 
  paper. 
  

  

  In 
  the 
  section 
  Goniostropha 
  CEhlert 
  collects 
  all 
  those 
  species 
  which 
  

   are 
  turriculated, 
  elongated, 
  having 
  angular 
  whorls 
  of 
  which 
  the 
  

   sinual 
  band, 
  nearly 
  always 
  limited 
  by 
  two 
  prominent 
  keels, 
  occupies 
  

   the 
  summit 
  ; 
  sometimes 
  there 
  are 
  additional 
  spiral 
  keels. 
  He 
  says 
  

   that 
  the 
  spire 
  has 
  no 
  umbilicus, 
  and 
  at 
  the 
  same 
  time 
  he 
  refers 
  to 
  

   this 
  section 
  Murchisonia 
  Jcendalensis, 
  M 
  c 
  Coy, 
  which 
  has 
  an 
  umbi- 
  

   licus. 
  IVIuch 
  weight, 
  however, 
  cannot 
  be 
  attached 
  to 
  the 
  presence 
  

   or 
  absence 
  of 
  an 
  umbilicus, 
  as 
  it 
  is 
  known 
  to 
  exist 
  in 
  some 
  members 
  

   and 
  not 
  in 
  others 
  of 
  the 
  same 
  species. 
  

  

  Of 
  the 
  species 
  I 
  am 
  about 
  to 
  describe, 
  one, 
  M. 
  subtilistriata, 
  may 
  

   undoubtedly 
  be 
  referred 
  to 
  this 
  section 
  ; 
  and 
  another, 
  M. 
  turriculata, 
  

   De 
  Kon., 
  may 
  at 
  any 
  rate 
  be 
  placed 
  here 
  provisionally, 
  as 
  it 
  agrees 
  

   in 
  general 
  characteristics, 
  with 
  the 
  exception 
  of 
  the 
  sinus 
  being 
  most 
  

   probably 
  situated 
  immediately 
  below 
  the 
  angle. 
  With 
  regard 
  to 
  the 
  

   remaining 
  species 
  M. 
  compacta, 
  its 
  characteristics 
  are 
  such 
  as 
  to 
  en- 
  

   title 
  it 
  to 
  a 
  place 
  in 
  a 
  separate 
  section. 
  

  

  * 
  " 
  Notes 
  upon 
  some 
  Carboniferous 
  Species 
  of 
  Murchisonia 
  in 
  our 
  Public 
  

   Museums," 
  Quart. 
  Journ. 
  Greol. 
  Soc. 
  Nov. 
  1887, 
  p. 
  620. 
  

   t 
  Geol. 
  Surv. 
  Canada, 
  dec. 
  i. 
  p. 
  18. 
  

  

  % 
  Bull. 
  Amer. 
  Mus. 
  Nat. 
  Hist. 
  vol. 
  i. 
  no. 
  8. 
  1886, 
  p. 
  311. 
  

   § 
  Bull, 
  de 
  la 
  Soc. 
  d'Etudes 
  Scientinques 
  d' 
  Angers, 
  1887, 
  pp. 
  13, 
  20. 
  

  

  